Retailer Aeon Co. is opening overseas stores faster than initially planned as the yen's climb to postwar highs boosts its purchasing power.

The opportunity to expand now is "too great" to miss, said Seiichi Chiba, chief financial officer at the nation's largest supermarket operator. "If we were to miss this strategic opportunity, we would not be able to recover for 10 or 20 years."

The supermarket giant is opening stores in China, Vietnam and Cambodia under plans to boost investment there to 25 percent of its total by 2013 from 8 percent in 2009.